First of all, there's Oedipus and the riddle of the Sphinx, which has happened before the action begins in Oedipus The King (released in Europe under the title "Oedipus Rex"). Now a new riddle faces Thebes -- they must de-plaguify themselves by finding the guy who killed King Laius. Oedipus cuts his way through the bureaucratic red-tape mumbo-jumbo at Thebes P.D. and gets after it with the Q&A:

ŒDIP. Yes; but where are they? How to track the course

Of guilt all shrouded in the doubtful past?

CREON. In this our land, so said he, those who seek

Shall find; unsought, we lose it utterly.

ŒDIP. Was it at home, or in the field, or else

In some strange land that Laius met his doom?

CREON. He went, so spake he, pilgrim-wise afar,

And nevermore came back as forth he went.

ŒDIP. Was there no courier, none who shared his road,

From whom, inquiring, one might learn the truth?

CREON. Dead are they all, save one who fled for fear,

And he had naught to tell but this:…

ŒDIP. [interrupting] And what was that? One fact might teach us much,

Had we but one small starting-point of hope.

I like the [interrupting] -- there are hardly any other stage directions, but Sophocles wants to make clear that Oedipus is like "The Closer" here.

Then, after some Strophes and Anti-strophes (this is where you'd put the commercials), they bring in Teiresias as the expert witness. And he speaks in riddles. So Oedipus flips over the table in the interrogation room (somehow my copy of the Harvard Classics omits this stage direction), and gets all bad-cop:

ŒDIP. Yes; I will not refrain, so fierce my wrath,

From speaking all my thought. I think that thou

Didst plot the deed, and do it, though the blow

Thy hands, it may be, dealt not. Hadst thou seen,

I would have said it was thy deed alone.

This is where Oedipus could have used the veteran partner who was one day away from retirement -- although, come to think of it, Oedipus is the guy who's one day away from retirement. And Teiresias fingers Oedipus right back, and then, after this outburst of clarity, starts talking in riddles again:

ŒDIP. [starting forward] What? Stay thy foot. What mortal gave me

birth?

TEIR. This day shall give thy birth, and work thy doom.

ŒDIP. What riddles dark and dim thou lov’st to speak.

TEIR. Yes. But thy skill excels in solving such.

A cool customer, that Teiresias. And scene! Tieresias must be well-connected, though, because Oedipus doesn't pistol-whip him (or javelin-whip him, to be historically accurate) until he tells the whole story.

I don't usually summarize to this extent, but most of the I.,i. excerpts I have to read are much duller than this. It helps Sophocles (who apparently was very graceful, the Introductory Note tells us that he was "the most perfectly balanced among the three great masters of Greek tragedy") that we're familiar with the story -- there's a lot less "as you and I both know" here, we can get Creon on with new information right away. And Oedipus is agitated right from the get-go, as befits a king of a plaguey city-state.